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I'm trying to create a regular expression in sieve. The implementation of sieve that I'm using is Dovecot Pigeonhole

I'm subscribed to github project updates and I receive emails from github with the subject in the format that looks like this:

Re: [Opserver] Create issues on Jira from Exception details page (#77)

There is a project name in square bracket included in the subject line. Here is the relevant part of my sieve script:

if address "From" "notifications@github.com" {
  if header :regex "subject" "\\[(.*)\\]" {
      set :lower :upperfirst "repository" "${1}";
      fileinto :create "Subscribtions.GitHub.${repository}"; stop;
  } else {
      fileinto :create "Subscribtions.GitHub"; stop;
  }
}

As you can see from the above, I'm moving the messages to appropriate project IMAP folders. So the message with the subject above will end up in Subscribtions.Github.Opserver

Unfortunately, there is one small problem with this script. If someone adds square brackets in the title of their github issue, the filter breaks. For example if the subject is:

[Project] [Please look at it] - very weird issue

The above filter will move the message to folder Subscribtions.Github.Project] [please look at it which is completely undesirable. I'd like it to be moved to Subscribtions.Github.Project anyway.

This happens because by default regular expressions are greedy. So they match the longest possible match. However when I try to fix it the usual way changing "\\[(.*)\\]" to "\\[(.*?)\\]" nothing seems to change.

How do I write this regular expression so that it acts as desired?

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1 回答 1

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答案是更改"\\[(.*)\\]"为"\\[([^]]*)\\]"。

通过阅读问题中链接的正则表达式规范，我们发现使用了POSIX 正则表达式。不幸的是，那些不支持非贪婪匹配。

但是，在上面给出的这种特殊情况下，有一种解决方法。

于 2015-02-23T20:14:06.350 回答